Yes you work at the low end on negs ALWAYS. You fix that in processing if need be. Don't you remember that bit about the shadows need what 2-3 min max to be full and then you can cut or extend time to control highlights? You pull or push. and Please the CIAS at RIT is second to who?
Next your over exposing to reduce apparent Highlight grain at the expense of shadow grain PERIOD ALWAYS. You can't stack it up in once place and not increase it in others. So sure the highs will look cleaner at the expense of the lows. Whatever.
you don't like Jacks comments. Why not ask Andy what he thinks of Jacks comments.
Your Cooks and Pani's Don't have shutters so WTF are you talking about? I personally don't chose to own cinema lenses but ok. I prefer to put that cost into a production budget and then I make more money because pay is based on % of production cost.
Leaf shutter. Wow you are so right. I just did a test with my Rodenstock 90mm f6.8 and the difference from f8 and f45 is about a 1/10 of a stop difernce. crazy I will stop using that shutter immediately. Or maybe my Elenchrom power packs aren't accurate but I did get the same exact reading with 5 pops at each aperture.
testing a lens for contrast? depends I guess it depends if you just want to measure it relative to other lens on the same stock or actually imperically measure it. Most of the people I know don't measure it but they pick lenses and systems based on the type of response the lens has.
Selenium and PAPER Even the IPI suggest reading this Thesis by an RIT master student.
and IPI still only reports the red spots in the use of selenium toner in regard to its use on black and white film not paper. Which is why even the IPI references that thesis.
Kodak Sepia Toner
In spite of having altered the toning method for Sepia Toner as well (see Toning) the
obtained results are very satisfactory. None of the samples displayed symptoms of
deterioration after the hydrogen peroxide fuming test. The %-density retention curves are
consistently high over the entire density range. Kodak's Elite paper appears to be the most
difficult to tone as the 65% density retention for Dmax marks the lowest value measured.
Despite the relatively high degree of conversion, the overall tone-change is not as dramatic
as one might expectfrom aSepia toner, llford Multigrade and Agfa Multicontrast both remain
almost neutral in tone. All other materials assumed a slight to moderate sepia tone, which is
not offensive or overly pronounced.-49-
Exposure to heat and humidity affected the two Agfa papers most. Oddly enough, in toning
both papers gained density. The incubations amply compensated for this gain and left the
samples with a net loss of @ 0.20 unitsfor Dmax.
This is not utterly surprising. Both papers make a
significantly
"warmer"
print which is
suggestive of a chloro-bromide as opposed to a pure silver bromide emulsion. A tentative
conclusion is that the toner has a more prominent effect on the slightly rounder particles of
the chloro-bromide emulsions.
But you are smarter then the IPI I get that.
On Tue, Apr 1, 2014 at 2:20 PM, karl shah-jenner <shahjen@xxxxxxxxxxxx> wrote:
Rand chooses to argue thusly:dont care to when i can test as many as I like here, and I've tested more than enough.
. I have ALL the testing I need. If you want to argue with the test
results of the copal test I posted you are welcome to email him.
that is what people refer to as 'grain'. they are not talking about the grain, but the holes between the grain. we all know this. Raising it like it's a grand revelation avoids agreeing that denser colours, denser tones look less grainy.. or more filled out (as the dyes run together and leave less gaps)
Second over exposing doesn't make grain less it makes it more and tighter
which LOOK like less grain when its MORE.
I don't put my money on anyone's name. names are irerelevant to a scientist.. only the facts have meaning and they should stand without names being dropped like confetti
I think they call this physics.
I would put money on Jack Karpens tri-x 400 shot at 400 being better
soup it the same, dear god - changing the development mostly affects contrast and has nothing to do with speed.
then anything shot at 200. I mean this is meticulous care. I know lots
of people that shoot tmax 400 at 200 but then it also comes down to how its
being process and what juice and water minerals and on and on and on.
I read this years back and laughed as loudly then as I did now. Did you know people also eat gelatin? did you also know the justification is that it's rich in protein? Common knowledge says protein is good for us, and thus it is advocated as a food source for many elderly and infirm. Whant to see how right that is? Gelatin is inedible to us - sure it's protein, but so is melamine. Good for cows, not for humans - we cannot digest it. it has contributed to much malnutrition and quite a few deaths, yet it is still sold as a food! myths abound in thsi world and they're very hard to kill, especially when the inexperienced cite experts and perpetuate the mis-truths.
Jack Karpen - School of Photographic Arts and Sciences at RIT
Reference: U.S. Navy manual of photography, vol. 1 & 2, 1947 edition.
It should be noted that photographic emulsion consists of silver
suspended in gelatin.
This is very similar to those holiday jello molds (so popular this time of
year) where odd bits of various fruits are suspended in colored (usually
green) and flavored gelatin.
it is suspended in a flexible solid, call it a plastic, call it an emulsion. no, nothing is moving in this suspension when it's dry and if you've ever worked with biological suspensions in gelatin you'll know not much migrates even when it's wet!I'd bet the fuzzy pics were more likely a result of poor aperture selection on the enlarger, or not allowing for the slight expansion and deformation of the neg when enlarging. David Vestal wrote extensively on this. It seems few bothered to heed his advice.
The similarity continues in that we know what occurs when the jello mold is
dropped or treated in a rough manner. The bits of fruit are displaced to a
greater or lesser degree. This same phenomena can be witnessed when viewing
student work. When viewing fuzzy pictures be sure to question students on
how the film was handled before processing
awesome.
If he caught us hold our stainless or aluminum film processing tanks in our
hands it was not good for you grade. I would say I learned much from jack
on the nature of what is the right way to process film to then apply that
towards the rest of my education.
agreed.
This still has ZERO to do with the ISO not being listed as correct.
a stated ISO mean something in most parts of the world, it means it complies with international standards.
Because they thought the resulting dies in the film where crap but looked
nice at different settings is a non point. Its an aesthetic choice not a
as designed to operate based on whatever it was they where shooting for.
They're German's the looked up some math and then did that exactly based
on what works in a LAB and over exposing it doesn't make the ISO WRONG its
makes it an aesthetic choice in how to use that film.
In this case it did not. This film was written up with rave reviews across the world for the richness of the colours and depth in the dark tones. However, the film speed - again Ilford Standard, was stated incorrectly. basic stuff. a whole bunch of students would demonstrate this each semester and shrug and go .. 'huh!' This college was (..was, ain't no more) internationally recognised as one of the three top places in the world for photography, specifically science photography - the place where Kodak staff were trained to work at the facility recognised by Koday as the best (of their)facilities in the world. Yeah, the students were trained to pick at things till they fell apart, like true scientists. Not to take anything on face value or because someone said so. Of course once all the microscopes, the electron microscope, the enlargers, cameras and such were auctioned off and the course dumbed down to get more warm, fee paying butts on seats it's reputation slipped.we know this Rand. Fact is the stuff looked fantastic when shot at near +2 stops over it's ISO. Looked great at 180 asa too, but at 50 it blew people away. Was it marketting? sure was. the 80's was when they were really ramping that stuff up. Fact remains it was 180 ASA flm and exposed at 50ASA it was 'over' exposed and looked good. It's not simply a latitude thing, this is where neg film performs best - on the straight line.
ISO is determined at a given amount of exposure such that its above
base+fog.
'hahaha, you dont know me. not even a little.
I will take my experience and work with people like the multi oscar winning
Mr. Miranda over you.
he built his own light meters when he realised the purchasable models were limited?
Heres why. If you are shooting in light sources that
are not what the meter does best then its you issues to know what the
spectral response of the film and meter are in relation what they where
created and tested for in ISO.
oh wait, he tested all the films himself and didn't rely on manufacturers blurb..
ISO is a standard. we have a standard here for shearing sheep. who cares? But if I compare a standard to a result, I start from the standard. If the standard says i'm overexposing then that's what that standard says. Even if the exposure looks substantially better that those who comply with The Standard.. fact is the standard is just a standard.you're wiggling.
So its not really over exposing then is
it?
tell that to all the people who crowed about the ligh meters in their Nikon/Canon?minolta/Pentaxes across the world.
Its properly exposing for the spectral sensitivity of the film to that
light source. If your meter is NOT designed to meter that light then it
would be pretty dumb to count on that being accurate for that light.
and when the exposure test shows the film to 180 ASA (american standard) or 100/XX DIN ISO (dont forget the DIN otherwise you're not complying with ISO!) you're saying it works best exposed to the toe. Like the Standard for determining speed. Even though speed determination has UTTERLY NOTHING to do with the aestheric look of the image, it's exposure range or anything else .. it merely reports the minimum sensitivity point, than that's the best way to go
So
You probably have to test to determine what those sensitivities are and the
EXPOSE CORRECTLY.
sheesh..
..on the toe of the curve.. where the most room for slight variation occur, where you are relying on the least sensitive part of the film - while ignoring the steep straight curve off up the sensitivity scale.. where you could reliably record way more than any paper could take advantage of - instead you want to work at the weakest point of the film because that's how the ISO was defined You're argiuing that to CORRECTLY expose a film you must do that?
As to speed, ISO, ASA or DIN - which one? Ilford or Kodak? they're different. Maybe I could define an ISO speed point - heck, there must be a dozen speed defenitions put forward over the years. some didnt even use the toe at all.I bought 50 gretag grey cards once for the college and put them under the densitometer. Ceramic calibration. no 2 were alike. we had blue, green, yellow, magenta, cyan. photography is a sloppy business
You know you can in many cases just use the right type
of Grey card.
I made 10 grey cards using a laser printer (black carbon on white bond paper) and 10 grey cards using RC paper, both types were, even between the two types - infinitely more accurate and showed substantially less colour shift over time than the 'professional' ones. amazing how something so simple could be ignored ..we used plasma years back, it was called carbon arc then . I have about 50 rods in the back yard..
I only have 3 types. Generic grey, Strobe card and a
3200 kelvin card. Then I have a chart of what strobe produce what value on
each card that I use regularly as well as the same notes for hot lights,
Keno's of most temp, Quartz, tungsten, Plasma (latest coolest thing
developed by a friend of mines brother growing in popularity in the film
world.)
and microfilm was the first to reveal that the original sepia toner (which worked) had thiourea in it, while the later toner(which didnt work) had none.. and left the film susceptible to redox blemishes. The guys who made their name in the photo game didnt like this contradiction so it was ignored. experiments have shown film and paper both suffer it, paper to a lesser extent as people often (luckily) didnt wash out all the thiosulfate fix, and as it decomposed as it does naturally, it formed sulfides which tone and protect the silver in the paper. people dont like this fact either. Doesnt agree with what they read.
Selenium and what medium? Microfilm no its not good for microfilm.
For paper prints yes its still recommended by the IPI. (image permanence
institute (at RIT) https://www.imagepermanenceinstitute.org
no, that's a simplification and it's downright wrong. in the example I gave, at f45 you can expect the shutter fully open 1/2-3 times longer than at a full shutter exposure. demonstrable, repeatable and a noted aberation and failing in leaf shutters irrespective of brand. who takes this into account when they make their exposures? almost no one.
The insignificant amount of time its take the leaf shutter to open andclose are pretty irrelevant and the way a copal operated negates it.
heck, who even tests the contrast of their lenses (beside me?). what effect does that have on light transmission? 10%, 15%.. adds up but no one really cares so it gets ignored and mistruths get spread around.yeah, yeah, so are mine.. I've got a 40-400 varotal f4 panavision lens, concave front and thorium elements.
>My Schneider leaf shutter mamiya lenses with seiko shutters at fstop of 2.8
are dead nuts accurate with so little fall of its barely measurable and
I've got a Cooktime for a link:
not visible from 1/30th to 1/500th. Slower well I use the camera's focal
plan shutter which is also dead nuts on. I think you are totally
neglecting speed vs distance in the design of the leaf shutter.
http://en.wikipedia.org/wiki/Shutter_%28photography%29
".. but as speeds approach their maximum the shutter is far from fully open for a significant part of the exposure time"you assume a lot Rand.
I just can't fathom the
type of error rates you are claiming and can only imagine an experiment
error or equipment that spend to much time near salt water or the Mines and
dust of West OZ.
Karl Shah-Jenner
(not my birth name)..
